44. Where a design has been registered in one or more classes of goods, the application of the proprietor of the design to register it in some one or more other classes shall not be refused, nor shall the registration thereof be invalidated- (a) on the ground of the design not being a new or original design, by reason only that it was so previously registered; or (b) on the ground of the design having been previously published in Bangladesh, by reason only that it has been applied to goods of any class in which it was so previously registered: Provided that such subsequent registration shall not extend the period of copyright in the design beyond that arising from previous registration.